(1) Field of the Invention
The present invention pertains to a head suspension for supporting a read/write head adjacent a rotating data storage device where electrical conductors extending across the head suspension are protected from contact and possible damage from a lifting arm by one or more standoffs. The standoffs project outwardly from the head suspension adjacent and beyond the electrical conductors where the standoffs will come into contact with the lifting arm as it passes beneath the head suspension.
(2) Description of the Related Art
Most personal computer systems today employ direct is access storage devices (DASD) or rigid disk drives for data storage. A conventional disk drive contains a spindle that is rotated by an electric motor at several thousand revolutions per minute while the disk drive is turned on. A plurality of magnetically coated recording disks are mounted on the spindle for rotation therewith at axially spaced positions along the spindle. The number of the disks and the composition of their magnetic material coating determines, in part, the data storage capacity of the disk drive.
Positioned adjacent the peripheries of the rotating disks is a head actuator column. The head actuator column has a plurality of actuator arms thereon, and each actuator arm supports one or more head suspensions that extend in cantilever fashion from the actuator arm to distal ends of the head suspensions. Dynamic storage devices, for example magnetic read/write heads, are supported on sliders at the distal ends of each of the head suspensions. The read/write heads communicate with the central processing unit (CPU) through a series of electrical conductors that extend across the longitudinal length of the head suspension. Various types of known electrical conductors are employed for this purpose including printed circuit conductors, flex circuit conductors, and electrical conductors formed directly on the head suspension by known methods such a vapor deposition or photolithography. These are commonly referred to as traces or integrated conductors. The plurality of actuator arms and their associated head suspensions support the read/write heads adjacent the top and bottom surfaces of each of the plurality of disks supported by the rotating spindle. The rotation of each of the disks creates a current of air adjacent the disk surface. Each of the sliders flies on the air flow with there being an extremely small clearance between the read/write head supported on the slider and the rotating disk surface.
There are basically two types of head actuators, rotary and linear actuators. The rotary actuator moves its head suspensions and their supported read/write heads where the linear actuator moves the head suspensions and their associated read/write heads across the surfaces of the rotating disks linearly. In both types of actuators, the read/write heads supported on the sliders at the distal ends of each of the head suspensions slide in unison on a cushion of flowing air created by the surfaces of the rotating disks. The lifting force of the cushion of flowing air that tends to move the slider and read/write head away from the surface of the disk is counterbalanced by a spring region of the head suspension that biases the slider and read/write head toward the surface of the rotating disk.
When the DASD is not in operation, the disks are not rotating and therefore the cushion of air that lifts each read/write head and slider against the bias of the head suspension spring region is not present. In order to prevent the read/write heads and sliders from contacting the disks when the DASD is first activated or when it is being shut down, a dynamic load/unload ramp or comb is typically employed.
The dynamic comb is basically comprised of a number of lifting arms corresponding to the number of head suspensions. The lifting arms project from the dynamic comb like the teeth of a comb. The dynamic comb may be attached to the base of the disk drive so that when the actuator assembly of a rotary actuator swings the head suspensions to the outer peripheries of the disks, the head suspensions contact the ramp-like structure of the stationary comb to lift them out of contact and away from the disk surfaces whenever the disk drive is non-operational. In this manner, the lifting arms of the dynamic comb hold each of the head suspensions in a position relative to the disks where the read/write head and slider of each of the head suspensions is positioned at the periphery of the disk and a small distance from the surface of the disk when the disks are not rotating, thus preventing the read/write heads and sliders from contacting the surfaces of the disks. The dynamic comb holds the read/write heads and sliders in spaced positions from the surfaces of the disk, both when the DASD is first activated prior to the actuator column moving the head suspensions over the surfaces of the disks and when the DASD is shut down and the actuator column moving the head suspensions from the surfaces of the disks. When the DASD is operating and the disks are rotated by the spindle the lifting arms of the dynamic comb are disengaged from the head suspensions and do not affect their operation.
During the manufacture of DASDs, it is also often necessary to lift and separate head suspensions mounted on the actuator arms of an actuator column to facilitate in some manufacturing process steps and to keep the head suspensions apart from one another to avoid damaging them by their coming into contact. In these situations, a shipping comb is used having lifting arms that are inserted beneath one side of the head suspensions to maintain the spacing between the suspensions. When the construction of the actuator assembly is complete it is often moved to another area in the manufacturing facility and often moved to a geographically separate manufacturing facility. The shipping comb remains with the actuator assembly as it is moved to prevent the head suspension assemblies from contacting each other. This is why this particular comb is typically referred to as a "shipping comb".
Another comb is often inserted between the head suspensions of the actuator assembly just prior to the head suspensions being slipped between the stack of disks during the assembly of the disk stack and the actuator assembly to the base of a disk drive. Once the heads on the head suspensions are in an appropriate location, the comb, typically called a "merging comb", is removed from the actuator assembly leaving the head suspensions sandwiched between the disks. The "shipping comb" described earlier could also be used for this purpose.
It has been observed that when lifting arms, either of a shipping comb, a merging comb or a dynamic comb, pass beneath the lateral edge and underside of a head suspension, at times the distal edge of the lifting arm will contact an edge of the head suspension causing damage to a component part of that head suspension. For example, the distal edge of a lifting arm may come into contact with a flexure as it moves beneath the head suspension causing damage to the flexure and affecting the operation of the head suspension. Also, at times the distal end of a lifting arm will come into contact with an electrical conductor of a head suspension as the lifting arm is move beneath a lateral edge and the underside of the head suspension, causing damage to that conductor. This is likely to occur with head suspensions employing traces or integrated conductors such as printed circuit conductors or other electrical conductors formed directly on the surface of the head suspension engaged by the lifting arm. What is needed to eliminate this problem is the design of a head suspension that protects its electrical conductors from contact with a lifting arm of either a shipping comb, a merging comb or a dynamic comb.